Er polythiols with epoxide resins polyetherpolythiols method of preparation and mixtures of polythioeth

ABSTRACT

POLYTHIOETHERPOLYTHIOLS WITH A THIOL FUNCTIONALITY GREATER THAN 2 ARE MADE BY REACTING A POLYTHIOL WITH A TRIENE, A TETRAENE OR MIXTURES THEREOF OR MIXTURES OF THE POLYENES WITH A DIENE, IN THE PRESENCE OF A FREE RADICAL GENERATING CATALYST. THE POLYTHIOETHERPOLYTHIOLS CAN BE REACTED WITH EPOXIDE RESINS TO EFFECT CURES OF THE LATTER.

United States Patent Oflice Patented Sept. 18, 1973 U.S. Cl. 260-47 EC 20 Claims ABSTRACT OF THE DISCLOSURE 'Polythioetherpolythiols with a thiol functionality greater than 2 are made by reacting a polythiol with a triene, a tetraene or mixtures thereof or mixtures of the polyenes with a diene, in the presence of a free radical generating catalyst. The polythioetherpolythiols can be reacted with epoxide resins to effect cures of the latter.

This application is a division of application Ser. No. 771,648 filed in my name on Oct. 29, 1968, now abandoned and refiled on Aug. 12, 1'97'1 as Ser. Nos. 171,331 and 171,333.

SUMMARY OF THE INVENTION This invention relates to new polythioetherpolythiols which are made by reacting a dithiol with a compound having 3 to S olefinically unsaturated linkages or groups, or a mixture of at least one of said compounds with a diolefinically unsaturated compound preferably in the presence of a free-radical initiating catalyst. The new polythioetherpolythiols have a thiol functionality greater than 2.05 and preferably have a functionality of 2.2 to 4.

The new compounds can be aliphatic, or they can contain cycloaliphatic, or aromatic groups.

The polyene reactant can be derived from an aliphatic hydrocarbon, an aromatic hydrocarbon such as a phenyl, biphenyl or naphthyl group, an alkylidene biphenyl group, a poly(vinyl) or polyallyl ether of a polyol having 3 to 12 C atoms and 3 or more vinyl or allyl ether groups, a heterocyclic N containing group, or an oxygenated pentavalent P group. The unsaturated group can be attached to any of the above groups either through a carbon or through an oxygen linkage.

DETAILED DESCRIPTION OF THE INVENTION Polythioetherpolymercaptans having an average of from about 2.05 to 4 or more thiol groups per molecule have been unknown prior to this invention. I have found that a very wide variety of polythioetherpolymercaptans can be made by reacting one or a mixture of polyenes with one or a mixture of polymercaptans, in a molar ratio such that there are more mercapto groups in the reaction mixture than carbon to carbon double bonds, in the pres ence of a free radical initiator as a catalyst. The polymercaptan will add across the carbon to carbon double bond and terminate in a free mercapto group.

The individual polyenes which can be reacted have at least 3 olefinically unsaturated sites. Alternatively, mixtures of such polyolefinically unsaturated compounds with diolefins or more highly unsaturated olefins can be employed to make the new compositions of the invention. The polyenes may contain other groups which are nonreactive with thiol or olefinic groups such as hydroxyl, chloro, bromo, cyano, carboalkoxy, or carbamido.

The polymercaptans can contain from 2 to 4 mercapto groups. The polymercaptan can be aliphatic, cycloaliphatic, aromatic or heterocyclic. The carbon atoms in the aliphatic, cycloaliphatic, aromatic or heterocyclic polymercaptans can be substituted with any other group which will not react with the olefinic unsaturation. Thus, the substituents can be halogens, alkyl groups, alkoxy groups, aryloxy groups, or cyano groups.

Representative polymercaptans have the generic formula Y(SH) where Y is the non-reactive portion of the molecule and n is an integer of 2 to 4 as defined above. Typical polymercaptans include ethanedithiol, propanedithiols, butanedithiol, pentanedithiol, hexanedithiol, heptanedithiols, octanedithiols, nonanedithiols, decanedithiols, benzene dithiols, tolyl dithiols, xylyldithiols, cyclohexyl dithiols, ethyl cyclohexyldithiol, a,a-dimercapto-p-xylene, 3,3 dimercaptodiethylether, 5,5 dimercaptodiethylsulfide.

Typical trienes which can be employed include 1,2,4 trivinylcyclohexane, triallylcyanurate, triallylisocyanurate, triallylphosphite, triallylphosphate, 1,2,3 triallyloxypropane, triallyl ethers of trimethylolpropanes or pentaerythritol, 2,6 'diiallyl-l-allyloxybenzene, 1-allyloxy-2,4-dia'l lyl-6-methoxybenzene, tri allyltrimesate, triallylacetyl citrate or any other triene having up to 30 C atoms.

Representative tetraenes include 1,4 diallyloxy-2,5-diallyl benzene, 2,2'-bis(4-allyloxy-3-allylphenyl)propane, tetraallyl ether of pentaerythritol, 1,3-diallyloxy-4,6-di allylbenzene.

Examples of dienes which can be utilized as coreactants with the trienes or tetraenes include 1,5-hexadiene, 4-vinylcyclohexene, d-limonene, dipentene, divinylbenzene, diallyl ethers of polyhydric alcohols: containing from 2-10 carbon atoms such as a diallyl ether of glycerol, 8. diallyl ether of pentaerythritol, the diallyl ether of ethylene glycol, diallyl phthialate, or diallyl adipate.

The reaction can be initiated by any free-radical source, such as the organic peroxides or Ihydroperoxides, examples of which are benzoyl peroxide or t-butyl hydroperoxide, the azonitriles, such as azoisobutyronitrile or, if catalyst contaminants are to be avoided, the initiator can be a radiation source such as ultraviolet light or gamma radiation, such as a cobalt 60 source. If the radiation sources are used as catalysts, the reaction can be run at ambient temperature, but with peroxides, hydroperoxides, or azonitriles the reaction temperature must be approximately the decomposition temperature of the organic catalyst. Generally a temperature range of from 50 to C. can be used, depending primarily on the catalyst used.

The reaction can be carried out at atmospheric pressure, under a superimposed pressure or under vacuum. Since pressure appears to have no effect on the reaction, it is preferred to operate at ambient pressure at the reaction temperature used.

Because of the complexity of the reaction, the exact structure of the final products is not known with certainty. Thus, for example, if trivinyl cyclohexane is reacted with ethanedithiol the following courses could result.

With other trienes or tetraenes some telemorization can also occur by bridging of two or more molecules of the triene or tetraene through a thioether linkage.

The higher the equivalent ratio of dithiol the more tri(thioetherthiol) will be formed. In practice, however, some of the higher molecular weight products will also be formed.

The proportions of the reactants can vary somewhat, but it is preferable to have at least 1.1 equivalent of -SH per double bond, and up to about equivalents of SH per double bond. Higher molar --SH ratios can be used but they will not react and serve only as diluent s. In running the reaction it is preferable to add the triene or tetraene or mixture thereof or mixtures containing a diene to the polythiol. However, the polyene and the polythiol can be added simultaneously into the reaction chamber, if desired.

The products formed are all liquids having viscosities from about 2 poise up to such high viscosity that measurement with a Gardner viscometer cannot be made.

The examples which follow are intended to illustrate, but not to limit the invention. All parts are by weight unless otherwise indicated.

Example 1 A two liter round-bottomed flask was charged with 643 parts of 1,2-ethanedithiol and 1 part of azobisisobutyronitrile. The mixture was heated to C. and 185 parts of 1,2,4-trivinylcyclohexane were added slowly over a four hour period. An additional part of azobisisobutyronitrile was added and the mixture was held at 70 C. for nine more hours. The product was charged to a flash still and 338 parts of unreacted ethanedithiol were removed by distilling to a pot temperature of about C. at 0.1 mm. pressure. The residue -was filtered to yield 448 parts of a product analyzing 15.6% 4H. It had a Gardner viscosity of X or about 12.9 poise.

Example 2 The procedure employed in preparing polythioetherpolymercaptans was the same as that described in Example 1.

Tabulated below are the data obtained from several runs, using various trienes and tetraenes with ethanedithiol and propanedithiol. Viscosity data, percent total sulfur, and SH equivalent weight are included in the table.

TAB LE I Olefin Ethane- Yield of Percent dithiol, product, Viscosity, SH, S, by Percent Grams Name grams grams poise eq. wt. wt. SH

243 1,2,4-trivinylcyelohexane 848 640 185 643 450 12. 9 206 16. 0 182 5 1,2,4-trlvinyleyclohexane 964 467 8. 5 180 18. 0 0 188 12.9 200 40. 4 16. 6 45.0.- 1,4-diallyloxy-2,5-diallylbenzene 180 68 -32 241 33. 6 13. 7 28.1-. 2,2'-bis(4-allyloxy-3-allylphenyl) propane 56 45 306 26.9 10.8 83 Trlallyleyanurate 188 147 123 223 33. 0 14. 8 188 142 252 31. 9 13. 1 188 225 84. 2 14. 7 188 134 -25 227 34. 5 14. 6 189 154 2. 15 192 36. 3 17. 15 235 354 12. 9 252 35. 6 13. 1 2 414 335 2. 9 246 34. 2 13. 4 98 do 3 283 200 2. 0 212 33. 8 15. 6 214 2,fi-diallyl-l-allyloxybenzene 564 444 10. 7 206 35.0 16.0 271 Allyl ether of pentaerythritol having an aver- 619 541 225 33. 5 14. 7

age of 8.29 allyl groups. 270 Allyl ether of pentaerythritol having an aver- 658 563 228 35. 2 14. 5

age of 3.77 allyl groups.

1 Very viscous. 1,3-propanedithlol used. I 1,2-propanedithiol used.

TABLE 11 Wt. of Analysis, percent Moles product Viscosity, SH, Olefin A (moles) Olefin B (moles) HSCH2CH2SH (g.) poise eq. wt. S SH 4-vlnyleyclohexene (0.30) Triallylcyauurate (0.30) 3.0 226 -17. 6 206 36. 4 16. 0 d-Lim0neI1e (0.30 -do 3.0 225 22. 7 219 34. 3 15. 1 4-vinylcyclohexene (0.25) 1,2,4-trivlnyleyclol1exane (0.375) 1. 0 d-Limoneue (0.25) 2,2-bi2S(4-allyloxy-8-allylphenyl) propane 2. 7 236 98. 5 245 31. 0 13. 5 d-Limonene (0.375) 2,2-bi1s2(4-a1ly10xy-3-allylphenyl) propane 2. 5 189 10. 7 220 32. 8 15.0 1,2,3-triallyloxypropane (0.50) 2,2-bis(4-allyloxyphenyDpropane (0.50) 5. 0 414 7. 0 228 30. 0 14.5 1.2.3-tr1a11y10Xypr0panB 4. 0 371 32.0 231 32.8 14.3

2-bis(4-a11y1oxy-3-a1ly1phenyl) propane 1 Very viscous.

The polythioetherpolythiols described herein are useful for curing epoxide resins. In each of the following tests a reaction product of a triene or tetraene or mixtures with a diene and ethanedithiol was blended in equivalent amounts with a diglycidyl ether of bisphenol A havane, triallyl cyanurate, triallyl isocyanurate, trivinyl isocyanurate, triallyl trimesate, triallyl citrate, triallyl phosphate, triallyl phosphite and up to 50 mol percent of a monomeric diene selected from the class of 1,5-hexadiene, 4-vinylcyclohexane, d-limonene, di-

lng an epox1de equivalent welght of about 190. Tabulatcd pentene, dlvmylbenzene, dlallyl ethers of polyhydrlc below are data obtained on 15 mil thick films. Where alcohols containing 2 to 10 C atoms and 2 to 4 OH cure did not begin immediately on mixing, the films were groups, diallyl adipate and diallyl phthalate with held at 40 F. until set. (B) a polythiol of the formula Y(SH),, wherein 12 TABLE III Wt 1 i hi i thioe tilei ether t Cure Cure polythiol, SH, eq. bisphenol catalyst, time Polyene reacted with dithioethane g. wt. A, g. g. minutes 1,4-dia1lyloxy-2,5-diallyl benzene 28.0 241 22. o 66 16 Triallylisocyanurate 28.5 252 21.5 .65 1,140 Do 2s. 5 252 21. 5 65 I 3 Trial1y1eyanurate 27. 0 22a 23. 0 69 1 5 Trivinylisocyanurate 27. 1 225 22. 9 69 (011920 allyl 23.2 245 21.9 66 13 allyl 2 plus d-Limonene (50/50 mol percent)--. Triallylcyanumte plus d-limonene (50/50 mol percent) 26. 7 219 23.3 70 11 Triellyl eyanurate plus 4-v'inylcyclohexane (50/50 mol percent)... 26. 0 206 24. 0 72 12 Triallyloxypropane plus wnmo allyl) 27.1 237.4 22.3 m7 111 'r 1 11 1 E /is h i 0X 0 I16 mo re np i ff? 25. 1 192 24. 9 75 ll 1 Benzyl dimethyl amine.

1 Tetramethyl guanadine.

I Started to exotherm in bottle while mixing.

4 Cured while mixing.

The cured films adhere well to glass, wood, or metal is an integer of from 2 to 4 and Y is selected from and thus can be used for coatings or for making self-supa saturated aliphatic hydrocarbon group having 2 to porting sheeting. C atoms, a phenylene group, a tolylene group, a

In another series of tests, bars Va inch x V2 inch x 5 xylylene group, a cyclohexyl group, an ethyl cycloinches were prepared by mixing .75 equivalent of a di- 40 hexyl group, a glycidyl ether of bisphenol A, having an epoxide equlvalent weight of about 190, with an equivalent amount -CH;CH1 of a polythioetherpolythiol. The curing catalyst in all instances was benzyl-dimethylamine. The cure temperature group, a --(CH O(CH group, or a was ambient. Tabulated below are the polymers reacted CH S(CH with a dithiol and the properties of the bars which re- 92 suited. group in a ratio so as to provide at least 1.1 SH

TABLE IV Polythioetherpolythiol SH, eq. Shore A Physical Polyene reacted Dithiol wt hardness properties Triallyloxypropane HSCQHASH 183 70 Flexible. Triallyloxypropane plus diallyl ether of bisphenol A (/50 mol percent) HSCQHSH 228 Very flexible. Triellyloxypropane plus (OHmC oallyl HSCZILSH 231 as Slightly flexible,

very tough.

allyl (50l50mol percent) HSCzHzSH 231 98 Slightlyflexible,

very tough. Triallyloxypropane OH; 212 62 Very flexible.

Hs oHh JH SH Do-- 7 M HSCzHzSH 252 69 Flexible. Do- HS(CH2)aSH 246 71 Do.

I claim:

1. A composition comprising equivalent per unsaturated group of (A), the reac (I) a 1,2 diepoxide and tion product being a polythioether polythiol having (11) the liquid reaction product of (A) at least one 70 a thiol functionality greater than 2.05, the said reacpolyallyl ether of a polyol having 3-12 C atoms and at least 3 allyl ether groups, a compound having a benzene nucleus which has attached thereto 1 to 2 allyl and 1 to 2 allyloxy groups wherein the sum of the allyl and allyloxy groups is 3 to 4, 2,2 bis(4 allyloxy-B-allyl phenyl) propane, trivinyl cyclohextion being carried out in the presence of a free radical generating catalyst. 2. The composition of claim 1 in which the diepoxide is a diglycidyl ether of bisphenol A.

3. The composition of claim 2 in which (A) is trivinyl cyclohexane.

4. The composition of claim 3 in which Y(SH) is a dithiol of 2-3 C atoms.

5. The composition of claim 1 in which the diepoxide is the diglycidyl ether of bisphenol A and (A) is triallyloxypropane and Y(SH) is a dithiol of 2-4 C atoms.

6. The composition of claim 1 in which the diepoxide is the diglycidyl ether of bisphenol A, (A) is a 50/50 mol mixture of triallyloxypropane and a diallyl ether of bisphenol A and Y(SH),, is ethanedithiol.

7. The composition of claim 1 in which the diepoxide is a diglycidyl ether of bisphenol A, (A) is a 50/50 mol mixture of triallyloxy propane and (crime allyl) I allyl and Y(Sl-i) is ethanedithiol.

8. The composition of claim in which Y(SH) is a dithiol of 3 C atoms.

9. The composition of claim 5 in which Y(SH) is a dithiol of 2 C atoms.

10. The composition of claim 5 in which Y(SH) is a dithiol of 4 C atoms.

11. The composition of claim 1 in which the diepoxide is the diglycidyl ether of bisphenol A, (A) is 1,4-diallyloxy-Z,5-diallylbenzene and Y(SH) is a dithiol of 2-4 C atoms.

12. The composition of claim 1 in which the diepoxide is the diglycidyl ether of bisphenol A, (A) is triallyl isocyanurate and Y(SH) is a dithiol of 2-4 C atoms.

13. The composition of claim 1 in which the diepoxide is the diglycidyl ether of bisphenol A, (A) is triallylcyanurate and Y-(SH) is a dithiol of 2-4 C atoms.

14. The composition of claim 13 in which Y(SH) is ethanedithiol.

15. The composition of claim 1 in which the diepoxide is a diglycidyl ether of bisphenol A, (A) is a mixture of (crime (@w allyl) allyl 2 and d-limonene and Y(SH) is a dithiol of 2-4 C atoms.

16. The composition of claim 15 in which Y(SH) is ethanedithiol.

17. The composition of claim 1 in which the diepoxide is a diglycidyl ether of bisphenol A, (A) is a mixture of triallyl cya-nurate and d-limonene and Y(SH) is a dithiol of 2-4 C atoms.

18. The composition of claim 17 in which Y(SH) is ethanedithiol.

19. The composition of claim 1 in which the diepoxide is a diglycidyl ether of bisphenol A, (A) is a mixture of triallylcyanurate and 4-vinyl cyclohexene and Y(SH) is a dithiol of 2.4 C atoms.

20. The composition of claim 19 in which Y(SH) is ethanedithiol.

References Cited UNITED STATES PATENTS 3,625,925 12/ 197 1 Oswald 26079 2,789,958 4/1957 Fettes et a1. 26047 3,505,166 4/1970 Jones et al. 26047 WILLIAM H. SHORT, Primary Examiner T. E. PERTILLA, Assistant Examiner US. Cl. X.R.

117-124 E, 127, 148; 26077.5 NC, 79, 79.5 C

22253? UNITED STATES PATENT OFFICE o CERTIFICATE OF CORRECTIQN Patent No. 3,759,871 Dated September 18, 1973 Inve t fl Richard A. Hickner It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

I" I j "I Column 2, line 26, delete "trime-thylolpropanes! and insert --trimethylolpropane-- Column 3, Table I, under the heading "Grams", fourth line, delete "45.0" and insert -40.5--

Column 5, Table III, ugder the heading "Cure Time Minutes", first line, delete "l6 and insert --l65- Column 5, line 39 delete "1/3" and insert ---l/2-- Column 5, Table IV, under the heading "Dithiol", fourth line, delete "HSC H SH" and insert -HSC H SH Column 5, Table IV, under the heading "Dithiol", seventh line, delete "HSC H SH" and insert --HSC H SH-- Column 6, line 5, delete "4-vinylcyclohexane" and insert -i4vinylcyclohe xene- Signed and sealed this 5th day of November 1974.

(SEAL) Attest:

:McCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents 

